全文获取类型
收费全文 | 2005篇 |
免费 | 36篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 55篇 |
综合类 | 5篇 |
化学工业 | 387篇 |
金属工艺 | 102篇 |
机械仪表 | 65篇 |
建筑科学 | 25篇 |
矿业工程 | 1篇 |
能源动力 | 46篇 |
轻工业 | 109篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
无线电 | 225篇 |
一般工业技术 | 261篇 |
冶金工业 | 625篇 |
原子能技术 | 36篇 |
自动化技术 | 104篇 |
出版年
2023年 | 7篇 |
2022年 | 15篇 |
2021年 | 32篇 |
2020年 | 8篇 |
2019年 | 13篇 |
2018年 | 22篇 |
2017年 | 7篇 |
2016年 | 22篇 |
2015年 | 21篇 |
2014年 | 27篇 |
2013年 | 69篇 |
2012年 | 38篇 |
2011年 | 69篇 |
2010年 | 53篇 |
2009年 | 71篇 |
2008年 | 74篇 |
2007年 | 61篇 |
2006年 | 43篇 |
2005年 | 56篇 |
2004年 | 52篇 |
2003年 | 52篇 |
2002年 | 52篇 |
2001年 | 56篇 |
2000年 | 46篇 |
1999年 | 58篇 |
1998年 | 215篇 |
1997年 | 159篇 |
1996年 | 114篇 |
1995年 | 65篇 |
1994年 | 56篇 |
1993年 | 59篇 |
1992年 | 32篇 |
1991年 | 24篇 |
1990年 | 22篇 |
1989年 | 18篇 |
1988年 | 18篇 |
1987年 | 20篇 |
1986年 | 9篇 |
1985年 | 15篇 |
1984年 | 14篇 |
1983年 | 8篇 |
1982年 | 23篇 |
1981年 | 17篇 |
1980年 | 21篇 |
1979年 | 24篇 |
1978年 | 7篇 |
1977年 | 18篇 |
1976年 | 36篇 |
1975年 | 11篇 |
1966年 | 4篇 |
排序方式: 共有2050条查询结果,搜索用时 865 毫秒
81.
Hiroaki Takeda Masataka Ohgaki Takashi Kizuki Kazuaki Hashimoto Yoshitomo Toda Shigekazu Udagawa Kimihiro Yamashita 《Journal of the American Ceramic Society》2000,83(11):2884-2886
The formation process of Ba2 La8 (SiO4 )6 O2 was clarified using thermogravimetry–differential thermal analysis (TG-DTA) and a high-temperature powder X-ray diffraction (HT-XRD) method. Phase changes identified from the HT-XRD data surprisingly corresponded to the weight loss and/or endothermic peaks observed in the TG-DTA curves. Raw material with the composition Ba2 La8 (SiO4 )6 O2 was completely reacted at 1400°C and produced only an apatite-type compound without a secondary phase. Moreover, the synthesis of Ba2+ x La8− x (SiO4 )6 O2−δ crystals with x = 0–2 was attempted using a solid-state reaction. 相似文献
82.
The stability of the centerless grinding process is very sensitive to the set-up conditions due to the uniqueness of the work-holding system. Centerless grinding produces precision components with high productivity only when the set-up condition is optimally chosen. This paper describes the effect of set-up conditions on three stability criteria of the centerless grinding system. It also presents guidelines for determining proper set-up conditions to avoid spinners, chatter vibration and roundness problems. Finally, an algorithm for providing the optimum set-up condition based on process aims is proposed and the simulation results are discussed. 相似文献
83.
84.
S.T. Nakagawa H. Hashimoto H. Kanda A. Okamoto M. Ohishi H. Saito G. Betz 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(8-9):1226-1228
In order to advance quantum computer after successful synthesis of a qubit (quantum-bit) using a NV (nitrogen-vacancy) center in diamond crystal, the innovation of a NOT processor is strongly demanded. A candidate of it can be one NV center associated with an additional N atom, which is called a NV–N center. Making use of a classical molecular dynamics simulation of N ion implantation into pure diamond with an energy of 200 eV, we have examined the crystallographic structure of “NV–N” centers. However, at low temperature of 30 K, most implanted N atoms became interstitials, thus it was difficult to identify even NV centers. 相似文献
85.
86.
Preparation of sharp-melting hard palm midfraction and its use as hard butter in chocolate 总被引:1,自引:0,他引:1
Satsuki Hashimoto Toru Nezu Hiroshi Arakawa Tomonori Ito Shoji Maruzeni 《Journal of the American Oil Chemists' Society》2001,78(5):455-460
Preparation of hard palm midfractions (PMF) and its use as a cocoa butter equivalent ingredient were studied. Hard PMF is
obtained by multistep fractionation of palm oil involving dry fractionation (DF) and/or solvent fractionation (SF), usually
using hexane or acetone. From our experience, in acetone, a polar solvent, symmetrical 1,3-disaturated triacylglycerols tend
to selectively crystallize more than nonsymmetrical 1,2- or 2,3-disaturated triacylglycerols, making it suitable for obtaining
the solid midfraction. Unfortunately, triacylglycerols are very soluble in hexane, and temperatures at least 15 degrees lower
than those required for acetone must be used for equivalent crystal yields. On the other hand, DF is a less expensive and
safer process. Thus, multistep fractionation combining DF and SF using acetone was developed to achieve sufficient removal
of high-melting components, and further enrichment of 1,3-dipalmitoyl-2-oleoylglycerol and the hard PMF was obtained by triple-step
fractionation of palm olein or double-step fractionation of soft PMF. Compared to conventional hard PMF, this hard PMF had
a steeper melting curve and better snapping and sharp-melting qualities when used in chocolate. Heat resistance of the hard
PMF chocolate was similar to the conventional hard PMF chocolate, and its bloom resistance could be improved by adding polyglycerol
fatty acid esters. 相似文献
87.
Generalized-Extended-State-Observer and Equivalent-Input-Disturbance Methods for Active Disturbance Rejection: Deep Observation and Comparison
下载免费PDF全文
![点击此处可从《IEEE/CAA Journal of Automatica Sinica》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jinhua She Kou Miyamoto Qing-Long Han Min Wu Hiroshi Hashimoto Qing-Guo Wang 《IEEE/CAA Journal of Automatica Sinica》2023,10(4):957-968
Active disturbance-rejection methods are effective in estimating and rejecting disturbances in both transient and steady-state responses.This paper presents a deep observation on and a comparison between two of those methods:the generalized extended-state observer(GESO) and the equivalent input disturbance(EID) from assumptions,system configurations,stability conditions,system design,disturbance-rejection performance,and extensibility.A time-domain index is introduced to assess the disturbance-r... 相似文献
88.
For a better understanding of the atmospheric rusting of iron and steels, the present work is aimed to explore the mechanism of formation of green rusts, Fe3O4, α-FeOOH, β-FeOOH, γ-FeOOH, δ-FeOOH and amorphous ferric oxyhydroxide in aqueous solution at room temperature. The formation processes on which end products are determined are strongly affected by the oxidation rate, pH and the structure and composition of initial and intermediate species of iron. The systematic diagram of formation processes of iron oxide and oxyhydroxides has been presented, in which both dissolved and solid species of iron are included. 相似文献
89.
Atmospheric rusting of mild and low alloy steels was studied by means of infra-red and far infra-red spectrophotometries, X-ray and electron diffraction methods and scanning electron microscopy. The rusting process can be interpreted on the basis of a previously reported diagram for rust formation in aqueous solution.A large amount of amorphous matter in rust formed in semi-rural atmosphere was identified by infra-red and far infra-red spectra as amorphous ferric oxyhydroxide, FeOx (OH)8–2x. The amorphous ferric oxyhydroxide rust on low alloy steel was dense and uniform, and contained a considerable amount of bound water. From these results it can be concluded that the amorphous ferric oxyhydroxide rust acts as a protective barrier against atmospheric rusting of the steels. Cu, P and Cr in low-alloy steels are inferred to favour the formation of crack-free, uniform rust layer and help to produce uniform amorphous ferric oxyhydroxide. 相似文献
90.
As a standard for identification of iron oxides by X-ray photoelectron spectroscopy, Fe2+ spectra are extracted from mixed Fe 2p3/2 spectra of Fe3+, Fe3+ and metallic states. The peaks of Fe2+ spectra are all located at binding energy of 708·5 eV. The width of Fe2+ spectrum seems to be dependent on crystallinity, and is 2·2 eV for a bulk crystalline oxide and 2·9 eV for an amorphous thin film under instrumental condition with FWHM of 1·3 eV for Au 4f7/2. 相似文献